Talented physicist brings nanoelectronics closer
The new generation of computers that we will use in the future may be partly attributable to the work of Russian physicist Anton Akhmerov. This talented theoretical physicist has made important breakthroughs in not one but two areas within nanoelectronics. He defended his thesis on 31 May.
The first area, graphene, has been the focus of much attention in recent years. Graphene is a single layer of carbon molecules that has special properties. It is the strongest material yet, is transparent and flexible, and electrons whizz through it as if they had no mass at all. There are many conceivable uses for graphene, such as for new types of monitors and transistors. Since Andre Geim and Konstantin Novoselov first made it in 2004 – for which they received the Nobel Prize in Physics last year – graphene has been a hype in physics.
When Akhmerov began his PhD research at the Leiden Institute of Physics (LION) he immediately jumped on this hype. He began with a feature of graphene that had not been given much attention in the past: the edges. ‘The theory of massless electrons always assumed infinitely large surfaces, but in practice graphene is made up of small pieces,’ comments his supervisor Prof. Carlo Beenakker. ‘These pieces have edges and something different happens there than inside the material.’
Akhmerov has come up with what are known as boundary conditions: a scientific description of how massless electrons rebound at an edge. This is important knowledge. ‘Anyone who works with graphene is confronted with these boundary conditions,’ says Beenakker. ‘Akhmerov’s work has been cited about a hundred times already.’ The group already talks jokingly of the ‘Akhmerov boundary conditions’, as many units and formulae in physics are named after the person who devised them.
However, once Akhmerov had completed that work he was only halfway through the time reserved for his PhD. He decided to delve into another subject, one that had just been discovered by physicists: topological materials. In physics this means materials with conductive properties that are impossible to break. Akhmerov investigated whether you can use these materials to build a quantum computer.
A quantum computer uses quantum mechanics and is many times more powerful than today’s computers, but it is difficult to maintain the special properties of quantum computers. Akhmerov has now described a number of ways in which to tackle this problem with the use of topological materials. Alongside graphene, this is also an important breakthrough in this field. He has now begun to work together with Leo Kouwenhoven’s group at Delft, which is going to build the computer he has described.
With its two different subjects, Akhmerov’s thesis has turned out to be a thick tome, but it has produced some very impressive results. ‘Anton already has the track record of a starting professor and that is very unusual,’ says Beenakker. The cherry on the cake is that one of the images from his thesis was used in an episode of the popular American comedy show The Big Bang Theory. In a certain sense, Akhmerov’s work has already been seen by an audience of millions.
Dirav and Majorana edge states in graphene and topological superconductors
Faculty of Science
Supervisor: Professor C.W.J. Beenakker
30 May 2011
(30 May 2011)